A conventional metamaterial optical member is disclosed in, for example, Patent Literature 1. In Patent Literature 1, a refractive index distribution type lens including a first region having a low refractive index and a second region having a high refractive index is disclosed and a refractive index distribution structure of the lens is configured by laminating metamaterials.
When the metamaterials are used, it is possible to artificially manufacture an optical member having a refractive index absent in the natural world (the square root of (permittivity μ×permeability ε): (εμ)1/2). That is, the metamaterial has a small metal piece, for example, as shown in Non-Patent Literature 1. This metamaterial configures an optical waveguide in which a silver layer and a germanium layer are laminated and which extends in a direction perpendicular to a lamination direction, a thickness of the silver layer is 4 nm, and a thickness of the germanium layer is 6 nm. A refractive index of 35 or more is implemented using this nanoscale structure.
When desired permeability of the metamaterial is obtained by forming a structure in a size less than or equal to ⅙ of an incident wavelength responsive to a magnetic field component of light (electromagnetic waves) or desired permittivity is obtained by forming a structure responsive to an electric field component of light (electromagnetic waves) as in the above-described Non-Patent Literature, it is possible to individually design the permittivity and the permeability defining the refractive index. Thus, it is possible to implement a refractive index material absent in the natural world. Because light collection impossible in the general lens is also possible when the metamaterial is used, applications in various fields are expected.